81641485 has 8 divisors (see below), whose sum is σ = 99576216. Its totient is φ = 64242240.

The previous prime is 81641419. The next prime is 81641489. The reversal of 81641485 is 58414618.

It can be written as a sum of positive squares in 4 ways, for example, as 7043716 + 74597769 = 2654^2 + 8637^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81641485 - 2²³ = 73252877 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81641489) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 133534 + ... + 134143.

It is an arithmetic number, because the mean of its divisors is an integer number (12447027).

Almost surely, 2^81641485 is an apocalyptic number.

It is an amenable number.

81641485 is a deficient number, since it is larger than the sum of its proper divisors (17934731).

81641485 is a wasteful number, since it uses less digits than its factorization.

81641485 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267743.

The product of its digits is 30720, while the sum is 37.

The square root of 81641485 is about 9035.5677740804. The cubic root of 81641485 is about 433.8140683874.

The spelling of 81641485 in words is "eighty-one million, six hundred forty-one thousand, four hundred eighty-five".